From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Comparison of three devices for preventing battery overcharging, with a detailed description of the bi-metal strip based Mentor device.
| Identifier | WestWitteringFiles\P\October1926-November1926\ Scan045 | |
| Date | 8th October 1926 guessed | |
| -6- Contd. at its full charging rate whenever the headlamps were on circuit. On switching off the headlamps the voltage would proceed to rise and shortly afterwards the electro-magnetic switch would be re-opened and the charge reduced. We are making bench tests of (1) This apparatus. (2) The Mentor thermally the operated high voltage indicator. (3) The voltmeter. to compare the operation of these three devices, each as an alternative proposition for the prevention of overcharging of the battery. A report on the results of these tests will be issued in due course. In the case of No.2 it should be stated that the Mentor device consists of two bi-metal strips, each one fixed at one end and carrying a contact at the other, the two contacts being opposite to one another. When these strips are at the same temperature (whatever that temperature) there is a definite gap between the contacts. One of the strips has a heating winding whose heating effect depends upon the voltage of the system. This strip becoming heated bends and causes its contact to make contact with that on the other strip. Change of ambient temperature bends the strips equally and eliminates any effect other than that due to the difference in temperature. The chosing of the contacts lights a red lamp. Contd. | ||